ENVIRONMENTAL analysis

Transcription

1 ENVIRONMENTAL analysis Analyzing Wastewater Effluents for PAH s and PBDE s Using the Agilent 7000 Triple Quadrupole GC/MS Solutions for Your Analytical Business Markets and Applications Programs Authors Dr. Mike Pinchin and Dr. Surinder Verik Anglian Water Services. Huntingdon, England Ken Brady SOLUTION NOTE Environmental Agilent Technologies, Inc. Cheadle, UK Abstract: An analytical method has been developed on the Agilent 7000 series Triple Quadrupole GC/MS for the analysis of polyaromatic hydrocarbons and polybrominated diphenyl ethers in wastewater. With a single extraction and no cleanup, this method meets the detection limit requirements of the United Kingdom Chemical Investigations Programme. Introduction The European Union Water Framework Directive (2000/60/EC) [1] promotes sustainable water use, including the long-term reduction of wastewater contaminant discharges to the aquatic environment. It is supplemented by the Priority Substances Daughter directive (PSDD), which establishes Environmental Quality Standards (EQSs) for priority substances. The EQSs define concentrations of chemical contaminants that are consistent with good chemical status in EU water bodies. A clearer understanding of the occurrence, concentration, and behavior in waste water treatment of these substances is required in order to address the PSDDobligations. To meet this challenge, UK Water Industry Research (UKWIR), in collaboration with the UK Environment Agency, has created the Chemical Investigations Programme (CIP) for the management and control of concentrations of priority substances. This program includes the quantification of risk and assessment of treatment options through the analysis of crude sewage, process streams, final effluents, and sludge.

2 The CIP focuses on several categories of priority substances, including polyaromatic hydrocarbons (PAHs) and polybrominated diphenyl ethers (PBDEs). This application note describes the development of a single extraction and sensitive method for the detection of these two classes of priority substances on the Agilent 7890 Series GC System coupled to the 7000 Triple Quadrupole GC/MS to meet the requirements of the CIP. It provides a single method for all 14 analytes, using only one extraction step and minimal or no cleanup, in both μg/l and ng/l concentrations. The reporting limits of the method are all below 3.0 ng/l, and well below the CIP analytical quality control (AQC) requirements. Experimental Reagents and Standards Reagent or Standard Source Calibration standard solutions were prepared by accuratelyweighing each analyte into a volumetric flask Hexane and dilutingwith hexane to generate a mixed stock solution. Ammonia solution Polyaromatic hydrocarbons Subsequent calibration and fortification solutions were created QMX Thaxted, UK (PAHs) by dilution from this stock using hexane. These calibration Polybrominated diphenyl ethers standards also contained a deuterated and 13C-labeled internal (PBDEs) standard cocktail. 13C internal standards (ISTD) Sigma Aldrich, UK HPLC grade, Rathburn Chemicals Ltd, UK 35% aqueous solution Accustandard, Kinesis, UK Instruments This method was developed on the Agilent 7890A GC with a multimode inlet (MMI) in solvent vent mode and a 4-mm liner packed with glass beads. The GC was coupled to the Agilent 7000B Triple Quadrupole GC/MS. The instrument conditions are listed in Table 1. GC run conditions Analytical column Injection volume Source Column 1: 30 m 0.25 mm, 0.25 μm HP-5. 5% Phenyl Methyl Siloxan (p/n 19091J-233) 25 μl Injection mode MMI in solvent mode, 4-mm liner packed with glass beads Inlet temperature 60 C Vent flow 100 ml/min for 0.09 minutes 60 C for 2 minutes Oven temperatures 25 C/min to 300 C; hold for 8.4 minutes Carrier gas Helium Velocity 30 cm/s constant flow mode Transfer line temp 300 C Run time 20 minutes MS Conditions Acquisition parameters EI mode; multiple reaction monitoring (MRM) Collision gas Nitrogen, constant flow, 1.5 ml/min Quench gas Helium, constant flow, 2.25 ml/min MS temperatures Source 300 C; Quadrupoles 230 C Table 1. GC and MS Instrument Conditions 2

3 Sample Collection, Preparation and Cleanup Samples were collected in 500-mL amber glass bottles. A 100-mL aliquot of the sample was taken and placed in a 250-mL amber screw cap bottle. A 50-μL amount of 35% aqueous ammonia solution was added by pipette, and the sample diluted with ultrapure water to approximately 200 ml. The internal standard solution was then added, followed by10 ml of hexane. The vessel was then placed on a bottle roller overnight (a minimum of 12 hours) to extract the analytes into the organic phase. The bottle was topped with ultrapure water. A pipette was used to take a 5-mL aliquot of the upper, organic hexane phase. This was then concentrated under a flow of nitrogen to 250 μl and transferred to a 2-mL autosampler vial for analysis by GC/MS/MS. The sample extracts were shown to be stable if stored refrigerated and analyzed within 28 days of extraction. Analysis Parameters The 7000 Triple Quadrupole GC/MS analysis parameters for the analytes and their internal standards are shown in Tables 2 and 3. Accuracy of Quantitation Results and Discussion Chromatographic Separation This method resolves eight PAH s and six PBDE s in less than 20 minutes, with the exception of benzo(b)fluoranthene and benzo(k) fluoranthene, which are partially resolved (Figure 1). Combined with the multiple reaction monitoring (MRM) MS detection, this chromatographic approach provides low interference and sensitive detection. Calibration curves for all of the PAH s and PBDE s spiked into final effluent provide excellent correlation coefficients (>.999) that assure accurate estimations of quantitation for all of the analytes. Representative quantifier ion traces and calibration curves are shown in Figures 2 and 3. Table 3. Internal Standard Analysis Parameters Table 2. MS/MS Analysis Parameters 3

4 Figure 1. Extracted ion current chromatogram of mid-level calibration standard. Figure 2. Representative quantifier ion traces and calibration curves for the first seven analytes eluting from the column. (Continued) 4

5 Figure 2. Representative quantifier ion traces and calibration curves for the first seven analytes eluting from the column. (Continued) 5

6 Figure 3. Representative quantifier ion traces and calibration curves for the last seven analytes eluting from the column. (Continued) 6

7 Figure 3. Representative quantifier ion traces and calibration curves for the last seven analytes eluting from the column. 7

8 Compound Lowest calibration level +3s +2s 2s 3s LOD Naphthalene 0.05 μg/l μg/l Anthracene 0.05 μg/l μg/l Fluoranthene 0.05 μg/l μg/l PBDE 28 2 ng/l ng/l PBDE 47 2 ng/l ng/l PBDE ng/l ng/l PBDE 99 2 ng/l ng/l Benzo(b)Fluoranthene μg/l μg/l Benzo(k)Fluoranthene μg/l μg/l Benzo(a)Pyrene μg/l μg/l PBDE ng/l ng/l PBDE ng/l ng/l Indeno(123cd)Pyrene μg/l μg/l Benzo(ghi)Perylene μg/l μg/l Table 3. Internal Standard Analysis Parameters Limits of Detection and/or Reporting Limit Table 4 lists the Analytical Quality Control (AQC) limits for each of the analytes. The Limit of Detection or reporting limit in this case varied from 3.0 ng/l for benzo(b) fluoranthene down to 0.06 ng/l for PBDE 28. References 1. Pollutants in Urban Waste Water and Sewage Sludge, environment/waste/sludge/pdf/ sludge_ pollutants_xsum.pdf Conclusions The 7000 Triple Quadrupole GC/MS System provided reproducible and sensitive detection of PAHs and PBDEs in wastewater down to levels of less than 3.0 ng/l. This single extraction method with no cleanup and no solvent exchange enables the laboratory to exceed the minimum reporting requirements of the United Kingdom Chemical Investigation Programme. For More information These data represent typical results. For more information on our products and services, visit our Web site at Agilent Products are for Research Use Only. Not for use in diagnostic procedures. Information, descriptions and specifications in this publication are subject to change without notice. Solutions for your analytical business Markets & Applications Programs Agilent Technologies, Inc Published in USA, June 25, EN